Few companies face as many challenges from the proliferation of digital technologies as contract printers like Quad, which is second only to Chicago-based R.R. Donnelley & Sons Co., the biggest printer in North America.

In addition to price and volume reductions from publishers of magazines, books and catalogs, which have seen their traditional print business lose ground to digital communications, Quad and other printing press operators are coping with upheaval and uncertainty at the U.S. Post Office, the money-losing channel for much of the nation's print marketing, direct mail, catalog printers and magazine publishers.

The Sussex-based company, with operations across Wisconsin, has been remaking itself through a half dozen acquisitions in the past four years. While annual sales are nearing $5 billion, Quad's reinvention is neither complete nor is it easy. It shut 19 plants in the past three years as the industry consolidates.

None of those closings was in Wisconsin, where Quad employs nearly 6,000.

Quad has struggled with unforeseen challenges in its latest acquisition, Vertis Holdings Inc., a rival printer based in Baltimore, which Quad acquired out of bankruptcy in January. In the conference call, Quadracci said Vertis amounts to a corporate turnaround, one that lost customers before the acquisition and which had failed to maintain its presses, leaving Quad to overhaul the machinery after the buyout.

Quad also felt the impact of the slowdown in key Latin American markets such as Mexico, Brazil and Argentina, where Quad has major customers and operations.

In the July-September quarter, net income fell 68% to $12.6 million, or 26 cents a share, from $39.7 million, or 84 cents, in the year earlier quarter.

Sales rose to $1.2 billion from $1.0 billion, but the entire gain was due to the acquisition of Vertis, which didn't belong to Quad until this year. Adjusting the sales as if Vertis had belonged to Quad in all of 2012 as well as 2013, sales would have fallen 7%, Quad said.

Investors had bid the stock progressively higher over the past few months. In light of Wednesday's figures, those gains suddenly appeared overbid, and the stock declined sharply.

Quad's shares fell throughout the day Wednesday and closed at $29.46 for a loss of $7.10, or more than 19%.